Jeannette R. Ferber

Urine bisphenol-A (BPA) level in relation to semen quality

OBJECTIVE To determine whether urine bisphenol-A (BPA) levels are associated with lower semen quality. DESIGN Cohort study. SETTING Four regions in China where high exposure to BPA in the workplace existed. PATIENT(S) 218 men with and without BPA exposure in the workplace. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) Semen parameters. RESULT(S) After adjustment for potential confounders using linear regression, increasing urine BPA level was statistically significantly associated with [1] decreased sperm concentration, [2] decreased total sperm count, [3] decreased sperm vitality, and [4] decreased sperm motility. Compared with men who did not have detectable urine BPA levels, those with detectable urine BPA had more than three times the risk of lowered sperm concentration and lower sperm vitality, more than four times the risk of lower sperm count, and more than twice the risk of lower sperm motility. The urine BPA level was not associated with semen volume or abnormal sperm morphology. Similar dose-response associations were observed among men with environmental BPA exposure at levels comparable with those in the U.S population. Despite a markedly reduced sample size, the inverse correlation between increased urine BPA levels and decreased sperm concentration and total sperm count remained statistically significant. CONCLUSION(S) These results provide the first epidemiologic evidence of an adverse effect of BPA on semen quality.

Occupational exposure to bisphenol-A (BPA) and the risk of Self-Reported Male Sexual Dysfunction

BACKGROUND Animal studies have suggested that bisphenol-A (BPA) is a potential human endocrine disrupter; but evidence from human studies is needed. METHODS We conducted an occupational cohort study to examine the effect of occupational exposure to BPA on the risk of male sexual dysfunction. Current workers from BPA-exposed and control factories were recruited. The exposed workers were exposed to very high BPA levels in their workplace. Male sexual function was ascertained through in-person interviews using a standard male sexual function inventory. RESULTS BPA-exposed workers had consistently higher risk of male sexual dysfunction across all domains of male sexual function than the unexposed workers. After controlling for matching variables and potential confounders, exposed workers had a significantly increased risk of reduced sexual desire [odds ratios (OR) = 3.9, 95% confidence interval: 1.8-8.6), erectile difficulty (OR = 4.5, 95% CI 2.1-9.8), ejaculation difficulty (OR = 7.1, 95% CI 2.9-17.6), and reduced satisfaction with sex life (OR = 3.9, 95% CI 2.3-6.6). A dose-response relationship was observed with an increasing level of cumulative BPA exposure associated with a higher risk of sexual dysfunction. Furthermore, compared with the unexposed workers, BPA-exposed workers reported significantly higher frequencies of reduced sexual function within 1 year of employment in the BPA-exposed factories. CONCLUSIONS Our findings provide the first evidence that exposure to BPA in the workplace could have an adverse effect on male sexual dysfunction.

Effectiveness of Seasonal Trivalent Influenza Vaccine for Preventing Influenza Virus Illness Among Pregnant Women: A Population-Based Case-Control Study During the 2010–2011 and 2011–2012 Influenza Seasons

BACKGROUND Although vaccination with trivalent inactivated influenza vaccine (TIV) is recommended for all pregnant women, no vaccine effectiveness (VE) studies of TIV in pregnant women have assessed laboratory-confirmed influenza outcomes. METHODS We conducted a case-control study over 2 influenza seasons (2010-2011 and 2011-2012) among Kaiser Permanente health plan members in 2 metropolitan areas in California and Oregon. We compared the proportion vaccinated among 100 influenza cases (confirmed by reverse transcription polymerase chain reaction) with the proportions vaccinated among 192 controls with acute respiratory illness (ARI) who tested negative for influenza and 200 controls without ARI (matched by season, site, and trimester). RESULTS Among influenza cases, 42% were vaccinated during the study season compared to 58% and 63% vaccinated among influenza-negative controls and matched ARI-negative controls, respectively. The adjusted VE of the current season vaccine against influenza A and B was 44% (95% confidence interval [CI], 5%-67%) using the influenza-negative controls and 53% (95% CI, 24%-72%) using the ARI-negative controls. Receipt of the prior seasons vaccine, however, had an effect similar to receipt of the current seasons vaccine. As such, vaccination in either or both seasons had statistically similar adjusted VE using influenza-negative controls (VE point estimates range = 51%-76%) and ARI-negative controls (48%-76%). CONCLUSIONS Influenza vaccination reduced the risk of ARI associated with laboratory-confirmed influenza among pregnant women by about one-half, similar to VE observed among all adults during these seasons.

Relationship Between Urine Bisphenol-A Level and Declining Male Sexual Function

The adverse effect of bisphenol-A (BPA) on the male reproductive system observed in animal studies has not been well examined in human populations. BPA is potentially a serious public health problem because of its widely detected presence in the human body. This study was conducted among 427 male workers in regions where high levels of BPA exposure existed. All participants provided urine samples, which were tested for BPA concentration using high-performance liquid chromatography. Male sexual dysfunction was ascertained using standard male sexual function inventories. Male sexual dysfunction was measured in 4 domains using 7 indices. After controlling for potential confounders using linear regression, increasing urine BPA level was associated with worsening male sexual function on a continuous scale. All 7 indices demonstrated this negative linear correlation. Increasing urine BPA level was associated with decreased sexual desire (P < .001), more difficulty having an erection (P < .001), lower ejaculation strength (P < .001), and lower level of overall satisfaction with sex life (P < .01). A similar negative correlation was also observed among participants exposed to BPA from only environmental sources (no occupational exposure to BPA), although the estimates in this group were less stable because of a smaller sample size. Our results reveal a correlation between a biological measure of urine BPA level and declining male sexual function. This finding may enhance the understanding of the BPA effect in human populations, and may have important public health implications given the widespread human exposure to BPA.

Exposure to magnetic fields and the risk of poor sperm quality

We conducted a population-based case-control study among healthy sperm donors to study exposure to magnetic fields (MFs) and poor sperm quality. All participants wore a meter to capture daily MF exposure. After controlling for confounders, compared to those with lower MF exposure, those whose 90th percentile MF level > or = 1.6mG had a two-fold increased risk of abnormal sperm motility and morphology (odds ratio (OR): 2.0, 95% confidence interval (CI): 1.0-3.9). Increasing duration of MF exposure above 1.6 mG further increased the risk (p=0.03 for trend test). Importantly, the association and dose-response relationship were strengthened when restricted to those whose measurement day reflected their typical day of the previous 3 months (a likely period of spermatogenesis). Age-adjusted Spearman Rank Order Correlations showed an inverse correlation between MF exposure and all semen parameters. Our study provides some evidence for the first time that MF exposure may have an adverse effect on sperm quality.

Infection and antibiotic use in infancy and risk of childhood obesity: a longitudinal birth cohort study

BACKGROUND Data from previous studies have suggested a possible association between antibiotic use in infancy and risk of childhood obesity, with implications for health-care delivery and obesity prevention strategies. However, whether the observed association was due to antibiotic use or underlying infection, or both, is unclear. We aimed to disentangle the effect of antibiotic use in infancy from that of underlying infection on the risk of childhood obesity. METHODS In this longitudinal birth cohort study, we included infants in the Kaiser Permanente Northern California population born between Jan 1, 1997, and March 31, 2013. We used electronic medical records to ascertain data for antibiotic use, infection diagnosis, and anthropometric measurements (and thus BMI and obesity status) from birth up to age 18 years. We used standard mixed-effects logistic regression for repeated measurements to analyse multiple BMI measurements per child (median five measurements) and to obtain odds ratios (ORs) and 95% CIs for obesity risk. We also did a substudy in 547 same-sex twin pairs with discordant exposure status to substantiate our findings. FINDINGS 260 556 individuals were included in our analysis. After controlling for maternal age, race or ethnic origin, pre-pregnancy BMI, preterm delivery, low birthweight, maternal antibiotic use, and infection during pregnancy, infection without antibiotic use in infancy was associated with an increased risk of childhood obesity compared with controls without infection (OR 1·25, 95% CI 1·20-1·29). A clear dose-response relation was seen between infection episodes and risk of childhood obesity (ptrend <0·0001). By contrast, compared with infants with untreated infection, antibiotic use during infancy was not associated with risk of childhood obesity (1·01, 0·98-1·04). Neither broad-spectrum nor narrow-spectrum antibiotics were associated with risk of childhood obesity. These findings were supported by the results of the twin set analysis. INTERPRETATION Infection, but not antibiotic use, during infancy is associated with risk of childhood obesity. This finding will need to be replicated in future studies. Although our results do not rule out a potential effect of antibiotics on microbiome composition and the use of antibiotics should always be judicious, they suggest that treatment of common infections with antibiotics in infancy is unlikely to be a main contributor to childhood obesity. FUNDING Kaiser Permanente Center for Effectiveness & Safety Research.

Severity of influenza and noninfluenza acute respiratory illness among pregnant women, 2010-2012.

OBJECTIVE The objective of the study was to identify characteristics of influenza illness contrasted with noninfluenza acute respiratory illness (ARI) in pregnant women. STUDY DESIGN ARI among pregnant women was identified through daily surveillance during 2 influenza seasons (2010-2012). Within 8 days of illness onset, nasopharyngeal swabs were collected, and an interview was conducted for symptoms and other characteristics. A follow-up telephone interview was conducted 1-2 weeks later, and medical records were extracted. Severity of illness was evaluated by self-assessment of 12 illness symptoms, subjective ratings of overall impairment, highest reported temperature, illness duration, and medical utilization. RESULTS Of 292 pregnant women with ARI, 100 tested positive for influenza viruses. Women with influenza illnesses reported higher symptom severity than those with noninfluenza ARI (median score, 18 vs 16 of 36; P < .05) and were more likely to report severe subjective feverishness (18% vs 5%; P < .001), myalgia (28% vs 14%; P < .005), cough (46% vs 30%; P < .01), and chills (25% vs 13%; P < .01). More influenza illnesses were associated with fever greater than 38.9°C (20% vs 5%; P < .001) and higher subjective impairment (mean score, 5.9 vs 4.8; P < .001). Differences in overall symptom severity, fever, cough, chills, early health care-seeking behavior, and impairment remained significant in multivariate models after adjusting for study site, season, age, vaccination status, and number of days since illness onset. CONCLUSION Influenza had a greater negative impact on pregnant women than noninfluenza ARIs, as indicated by symptom severity and greater likelihood of elevated temperature. These results highlight the importance of preventing and treating influenza illnesses in pregnant women.

Results of a pilot study using self-collected mid-turbinate nasal swabs for detection of influenza virus infection among pregnant women.

We evaluated the feasibility of asking pregnant women to self‐collect and ship respiratory specimens.

A Prospective Study of In-utero Exposure to Magnetic Fields and the Risk of Childhood Obesity

We conducted a prospective study to examine whether in-utero exposure to magnetic fields (MFs) increases the risk of childhood obesity. Participating women carried a meter measuring MF levels during pregnancy and 733 of their children were followed up to 13 years to collect clinically recorded information on growth patterns with 33 weight measurements per child on average. Prenatal exposure to high MF level was associated with increased risk of being obese in offspring than those with lower MF level (odds ratio = 1.69, 95% confidence interval: 1.01–2.84). The association demonstrated a dose-response relationship and was stronger (more than 2.3 fold increased risk) among children who were followed up to the end of the study. The association existed only for persistent obesity, but not for transitory (unlikely) obesity. Maternal exposure to high MF during pregnancy may be a new and previously unknown factor contributing to the world-wide epidemic of childhood obesity/overweight.

Exposure to Magnetic Field Non-Ionizing Radiation and the Risk of Miscarriage: A Prospective Cohort Study

Magnetic field (MF) non-ionizing radiation is widespread and everyone is exposed to some degree. This prospective cohort study of 913 pregnant women examined the association between high MF exposure and miscarriage risk. Cox (proportional hazards) regression was used to examine the association. After controlling for multiple other factors, women who were exposed to higher MF levels had 2.72 times the risk of miscarriage (hazard ratio = 2.72, 95% CI: 1.42–5.19) than those with lower MF exposure. The increased risk of miscarriage associated with high MF was consistently observed regardless of the sources of high MF. The association was much stronger if MF was measured on a typical day of participants’ pregnancies. The finding also demonstrated that accurate measurement of MF exposure is vital for examining MF health effects. This study provides fresh evidence, directly from a human population, that MF non-ionizing radiation could have adverse biological impacts on human health.